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Regierungs-Oberinspektor Fritz Menzer:

Cryptographic Inventor Extraordinaire

DAVID P MOWRY

This anic.:le is classified TOP SECRET CODEWORD in its entirety because the sources from which if W(;IS derived are all so classified.

It weighed one and rhree-quarter pounds and was ~pring-drfren. According to German authorities. ir was at leasr as secure as rhe Enigma. The Germans intended to have 1,000 available by Ocrober 1945 and to mass-produce I 0, 000 per month by January 1946. The Schfusselkaste11, or Cipher Box, would have replaced the Enigma below the level of division. If ii had been introduced in 1942, while the German star was in the ascendant, it could have changed the course of the war. Nineteen forty-five was, of course, too late. In 1942. the resulting loss of intelligence to the Allies would have af Jeered rhe outcome of the North African campaign and the Baale of the Atlantic, as well as subsequent campaigns. The inventor of the Schfusse/kasten, and other cipher devices, was Regierungs-Oberinspektor Fritz Menzer, of OKW/ Chi, the Cr}ptologic Section of the German Army High Command. 1

THE CAREER OF OBERINSPEKTOR MENZER

Os twin Fritz Menzer was born 6 April 1908 in rhe village of Herrndorf in Saxony, the youngest of four children of a small businessman. After completing elementary school and an apprenticeship as a toolmaker, he enlisted in the Reichswehr in 1926 as a mechanic and was assigned to a motor battalion in Leipzig. 2

Menzer had already developed an interest in cryptography and was granted his first patent in 1934, for a "combined measuring apparatus for angles and lengths, the data [from which was] expressed in an enciphered form in a four-place combination of letters." Based on his work on this device, he was permitted to attend a course for radio technicians at the Army Signal School. Jn May 1935 he was transferred to OK W /Chi to further

• develop his invention. Here he received his first formal training in cryptanalysis under the instruction of Ministerial Director Wilhelm Fenner. i

A year later, he had developed two methods for solving Hagelin C-36 encipherment and had developed an analytical method for the solution of the German Army Enigma. As a result, Menzer was ordered to establish a section in OKW/Chi to test foreign cryptosystems, to develop and test the security of German cryptosystems, and to construct cryptanalytic aids. Thus, at the age of 28, Menzer became the chief of communications security for the German Army. In his curriculum vitae, Menzer notes, "Since the troops and their command, because of their ignorance of the scientific status of cryptanalytic methods, regarded encipherment as a drag on modern communications technique, I often had to overcome great difficulties to put through my ideas." During this period, 1935 to 1938, Menzer also attended a special school for administration and economics. 4

Menzer's enlistment expired on 31 May 1938, and he was discharged from active duty with the rank of Senior Radio Technician. He "cot)verted'' to civilian status, retaining his

' position. On 1 April 1940, he was promoted to the rank of Superior Government Inspector. Early in 1942, because of the increased requirements for long-range communi­cations and because of increased emphasis on cryptosecurity, Menzer's section was broken up into three functional subsections. The Armed Forces, in general, had always been able

t l

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6 1212roved for Release b)' NSA on Ot-13-2005 i:iursuant to E.O. 12958, as amendecl

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to submit their cryptosystems to OK W /Chi for evaluation, but had not been required to do so. Until October 1943, when Keitel. Chief of the OK W, issued an order specifying that no new ciphers could be introduced by any branch of the Armed Forces or government ~gency without prior approval by OKW/Chi, only the Abwehr (Military Intelligence) had done so. In 1942, after the breakup of Menzer's section , Admiral Canaris, the Chief of the Abwehr, charged Menzer with testing the security of Abwehr cryptosystems. 5

Menzer found the Abwehr's systems to be depressingly inadequate, and in the summer of 1943, revamped all of the Abwehr hand systems then in use. He introduced the "ABC Schlussel," "Procedure 62." and "Procedure 40," all of which were double transposition­substitution systems; and the Schliisselrad, or Cipher Wheel, a hand operated autoclave, i.e., self-generating key cipher device .6

From April 1942 on, Menzer worked for the Abwehr as Technical Consultant in Cryptography. In this position , he traveled extensively on inspection trips and lectured officers and men on the principles of communications security . Late in the war his section was moved from Berlin to Werfen, Austria, where, on 8 May 1945 , he was taken prisoner by the American forces and interned at Camp Heufeld near Munich . He was released on 17 June and went to Leipzig. On 22 September he transferred his residence from Berlin to Zschopau in Saxony, the Russian Zone. He was hired as a technical teacher for metal· classes at the City Industrial School of Zschopau in January 1946. In November he was dismissed, because as a former member of the Wehrmacht, he was not eligible for a teaching position. He then established his own business in Zschopau, a workshop that employed seriously disabled veterans in the making of ladies' brooches. 7

AFTER THE WAR

In early July 194 7, the headquarters of the U.S. 7707 European Command Intelligence : Center (ECICJ began trying to arrange to interrogate Menzer regarding his cryptographic . work during the war. It was known that he sometimes visited Berlin, and an atrempt was made to persuade him to come there for a two-week stay. At this point, Menzer's life : began to resemble an Eric Ambler spy story.

Menzer's father-in-law and several neighbors were arrested by the Russians on 20 : August, while Menzer and his family were on holiday. A man named l!hlig, who had ; worked with Menzer in OK W/Chi, contacted Menzer and told him that he (Uhlig) was ~­

supposed to induce Menzer to come to the American Zone. In the meantime, the 7707 ' ECIC had been informed, without Menzer's knowledge, that Menzer was living in difficult .. · conditions in the Russian Zone and that he would insist on the transfer of himself, his family, and a "personal friend" (apparently Uhlig) to the American Zone .

According to a later statement by Menzer, Uhlig was a Soviet agent and was probably the person who had started the rumor that Menzer was in difficulty. In any case, Menzer ' considered the entire affair co be "preposterous ' ' but finally agreed to meet with the .· Americans in Berlin on 8 September. Menzer went to Berlin and was flown to Oberursel . with an American intelligence officer. Uhlig, and two other Germans. 8

In Oberursel, Menzer became very suspicious of Uhlig, particularly after he found out that Uhlig had told the Americans that he could go back to Zschopau and remove Menzer's furniture to the West. Feeling very dissatisfied with the whole situation, Menzer left Oberursel on his own on 12 September and returned to Zschopau. On 20 September, a message was brought to Menzer's home informing him that the President of the Chamber of Industry and Commerce wanted to speak to him at the Town Hall. When he arrived for the meeting, Menzer was arrested by the Russians and taken to the prison in Dresden.

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F

In Dresden, Menzer was interrogat~

wanted to know the details of his mee Uhlig, who had requested this of him '

Menzer was held in solitary confiner but, apparently, not mistreated. It was Uhlig was a Soviet agent and that tht (Menzer) to escape to the West thro establish Uhlig's bona tides and secure

Finally, on 13 March 1948. Menzer a spy for the Russians . He was orderec of Uhlig's willingness to work for the truthfully on his contacts with Uhlig. ' had no interest in moving to the Wes that he was being watched closely and Another factor causing him to delay before fleeing . Jn April 1949 he had m his family fled to West Berlin, wherf removed to West Germany in June documents until 195 I. 11

MENZER'S INVENTIONS

During Menzer's service with OK W, for a number of advances in the science was to adapt the use of Hagelin pin

cryptoequipment. The two major types of cryptoequi

were the Enigma and machines made stepped once with each encipherment "length" wheels. In the Enigma, moti1 the starting point of the cycle on each

such motions unpredictable. The Luckenf"ul/erwalze. Normal Er

respect to the rotor) ring with a sin~

blocking wheel which regulated the dri reading position, the next subordinat1 Luckenf iillerwalze. the notch ring was which could be filled in to make them

subordinate rotor . 12

The Sehl iisselgdat 39. Invented b coupled three Hagelin pin wheels with the rotors. All three wheels steppe1 according to normal Enigma rules , exc( wheel prevented the coupled rotor fro 263 = 17 ,576 characters . When set u Schliisselgerat 39 had a cycle length of as the cycle length of the unmodified E

The Schli.isselgerat 39 was fully aut• pla[n and cipher letters were printec

groups.

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1tion, bUL had not been required to do OK W, issued an order specifying that of the Armed Forces or government

he Abwehr 1Military Inrelligence) had ion, Admiral Canaris, the Chief of the Abwehr cryptosystems. 1

;singly inadequate, and in the summer then in use. He introduced the "ABC 111 of which were double transposition­:r Wheel, a hand operated autoclave,

Abwehr as Technical Consultant in vely on inspection trips and lectured s security. Late in the war his section n 8 May 1945, he was taken prisoner :ld near Munich. He was released on ansferred his residence from Berlin to ired as a technical teacher for metal January 1946. In November he was

:hrmacht, he was not eligible for a iness in Zschopau, a workshop that · ladies' brooches. 7

'707 European Command Intelligence : Menzer regarding his cryptographic es visited Berlin, and an attempt was k stay. At this point, Menzer's life

re arrested by the Russians on 20 lay. A man named Uhlig, who had :r and told him that he (Uhlig) was n Zone. In the meantime, the 7707 ~e, that Menzer was living in difficult nsist on the transfer of himself, his the American Zone.

'las a Soviet agent and was probably 'as in difficulty. ln any case, Menzer mt finally agreed to meet with the Q Berlin and was flown to Oberursel other Germans. 8

hlig, particularly after he found out go back to Zschopau and remove ed with the whole situation, Menzer ned to Zschopau. On 20 September, m that the President of the Chamber the Town Hall. When he arrived for taken to the prison in Dresden.

FRITZ .MENZER

Jn Dresden, Menzer was interrogated initially by 20 Russian officers in uniform, who wanted to know the derails or l1is meetings with the Americans. Omitting any mention of Uhlig, who had requested this of him at Oberursel, Menzer described what had happened. 9

Menzer was held in solitary confinement for six months and was frequently interrogated but, apparently, not mistreated. It was while in prison that Menzer became convinced that Uhlig was a Soviet agent and that the entire situation was a set-up designed to get him (Menzer) to escape to the West through Uhlig's good offices and with Uhlig, thus to establish Uhlig's bona fides and secure a good job for him with American intelligence. 10

Finally, on 13 March 1948, Menzer was released, after signing an agreement to work as a spy for the Russians. He was ordered to spy on Uhlig, apparently to continue the fiction of Uhlig's willingness to work for the Americans. Menzer did so, reporting dutifully and truthfully on his contacts with Uhlig. When the charade had started, in 1947, Menzer had had no interest in moving to the West. His attitude had now changed. However, he felt that he was being watched closely and decided to wait for a more favorable opportunity. Another factor causing him to delay was the fact that he wanted to clear up his debts before fleeing. In April 1949 he had met all of his financial obligations and in May he and his family fled to West Berlin, where he surrendere~ to American au~horitic_]_ H 0 "'n

removed to West Germany in June 1948. He continued to be mentioned It! documents until 195 I. 11 / ....__ ___ _

MENZER'S INVENTIONS

During Menzer's service with OK W/Chi and the Abwehr ( 1935-45), be was responsible for a number of advances in the science of machine cryptography. In gerieral, his procedure was to adapt the use of Hagelin pin wheels to provide for irregular wheel motion in cryptoequipment.

The two major types of cryptoequipment used by the Germans before World War II were the Enigma and machines made under the Hagelin patents. In the latter, all wheels stepped once with each encipherment; the cycle was extended by the use of different "length" wheels. In the Enigma, motion was odometer-type/with the only variation being tbe starting point of the cycle on each rotor. Menzer's inventions were designed to make such motions unpredictable.

The Luckenfu/lerwa/ze. Normal Enigma rotors had on the left side a movable (with respect to the rotor) ring with a single drive notch/ and on the right a fixed 26-notch blocking wheel which regulated the drive. When the drive notch on one rotor reached the reading position, the next subordinate rotor wo.uld advance one position. In Menzer's Luckenf iillerwalze, the notch ring was fixed on the rotor and had 26 drive notches, any of which could be filled in to make them inactive/thus providing for irregular stepping of the subordinate rotor. 12

The Sch/"l1sse/gera1 39. Invented by Menzer in 19 39, this development of Enigma coupled three Hagelin pin wheels with the Enigma rotors to provide variable stepping of the rotors. All three wheels stepped once with each enciphermen!. Rotors stepped according to normal Enigma rules, except that an active pin at the reading station for a pin wheel prevented the coupled rotor from stepping. Tbe cycle for an unmodified Enigma is 263 = 17,576 characters. When set up in accordance with Menzer's instructions, the Schliisselgerat 39 had a cycle length of 2. 7x I 08 characters-more than 15,000 times as long as the cycle length of the unm6dified Enigma.

The Schliisselgerat 39 was fully automatic, in that when a letter key was pressed, the plain and cipher letrers were printed on separate paper tapes, divided into five-letter groups.

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Because of constant technical improvements on the part of the Ordnance Department, development of the Schliisselgerat 39 was not completed until 1944. 13

The Sehl usselgerat 41. This mechanical cipher machine, invented in 1941, was based on Hagelin encipherment but included a mechanism for variably stepping the Hagelin wheels.

The Schliisselgerat 41 had six pin wheels which were mutually prime. The first five of these wheels had kicks of I, 2, 4, 8, and I 0 respectively. The sixth wheel made these kicks positive or negative .

The enciphering cycle (encipherment of one lerter) consisted of three elements:

I. This took place if and only if the sixth wheel had an active pin in the "motion index position." If this were the case, then all of the following occurred: Wheel I moved one step. Each of the remaining four wheels moved one step unless the wheel to its left had an active pin in the "molion index position , " in which case it would move cwo steps.

2. A key kick was generated which was the sum of all che kicks of wheels which had active pins in the " kick index position." If, however, the sixlh wheel had an active pin in the "kick index position," the key kick would be 25 minus the sum of all the ocher kicks. In other words, under such a circumstance, the key would complement icself.

3. This was identical to Step I , except that it occurred whether or not Wheel 6 had an accive pin in the "motion index position." In this step, Wheel 6 also stepped one or two positions, depending on the slate of Wheel 5. 14

The original specifications called for a lightweight, durable machine to be used by units forward of division. Menzer designed it to provide a cipher tape and to be keyboard operated in order to improve the speed of enciphermenl. As a result of the keyboard operation, he was able 10 redesign the arrangement of letters on the print wheels to flatten the cipher frequency count.

Because of !he wartime shortages of aluminum and magnesium, the machine ended up weighing between 12 and 15 kilograms , too heavy for fielci use . Removal of the keyboard would have lighcened the machine, but the redesign of the print wheels prevented their being used directly for encipherment. Production stopped because no one knew what to do. Abouc 1,000 machines had been constructed, and these were distributed to the Abwehr, which began using them in 1944 .15

attack. In 1947, Frank Lewis, in WDGAS-71, stated that if a mechanically rehable machine

could be built embodying the same principles as the Schliisselgerat 41, it would undoubtedly be a valuable asset. He noted that, because of the key complementing characteristic of !he machine, statistical tests did not seem to offer any particular promise for solucion .16

The Sehl ·usselkasten. The Cipher Box was a mechanical cipher device making use of the principles of sliding strips. Basically, it was a three-quarter pound aluminum box containing three Hagelin pin wheels and a coil spring which determined the stepping of a sliding strip or "slide rule" on the top of the box .

Two alphabets were written on the slide rule, 13 characters of each on the fixed base, and 13 characters of each on the top and bottom of the sliding strip. The latter were so written that only one alphabet at a time was in phase. Alphabets could be changed as often as desired .

In use, the slide was pulled to !he right untii it stopped. winding the spring that drove the mechanism. Pressing a button released the slide to move left. When ac either or bolh of the reading positions AiA2 the pins were a ll inactive , the slide stopped and encipherment

I Te.YI C0/1/1111/~d 111/ page JUI

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1 . 4 . I b) EO 1 . 4 . I c ) Fig. I . S

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1e part of 1he Ordnance Depanment, :ted unril 1944. 13

:hine, invented in 194 I , was based on variably stepping the Hagelin wheels. vere mutually prime. The first five of 1ely. The sixth wheel made these kicks

consis1ed of three elements:

1ad an active pin in the "motion index 'owing occurred: Wheel I moved one tep unless the wheel to its left had an case it would move two steps .

of all the kicks of wheels which had , !he sixth wheel bad an active pin in minus the sum of all the other kicks.

muld complement itself. urred whether or not Wheel 6 had an ep, Wheel 6 also stepped one or two

durable machine to be used by units a cipher tape and to be keyboard

rment. As a result of the keyboard · letters on the print wheels to flatten

I magnesium, the machine ended up · field use. Removal of the keyboard of the print wheels prevented their

>ed because no one knew what to do. !Se were distribu1ed to !he Abwehr,

i.....__li tat if a mechanically reliable machine l 1liisselgeriit 41, it would undoubtedly complementing characteristic of the

icular promise for solution. 16

nical cipher device making use of the .rter pound aluminum box containing mined the stepping of a sliding strip

haracters of each on the fixed base, the sliding strip. The laeter were so Alphabets could be changed as often

pped, winding 1he spring that drove move left. When at either or both of the slide stopped and encipherment

!Tex1 cn111i1111ed 011 page 301

'. \

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FRITZ MENZER

Fig. I. Schliisselgeriil 41. Ready for use.

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Fi~ . 2. Sc hlii~sflg~ral 41. Fa ;e of rnainte nanct "a' not a s trong point of the SG- 41. Rcmo1·al of thr l"OHr i1nohcd n•mo1·ing all nttrna l knobs and crlnk< and then undoing six su~ws .

.. --~-····· -- · .. .. ------·--·------

0 .-

0 0 0 H 0

I\) ..J 01 ..J 0 0 l'I)

I_, -...J

fig . 2. Schliis,elgHat 41. Ease of maintenance was not~ strong point of the SG-41. Rcmo•·al of th~ cover inH1lrcd rcmo•·ing ~II external knot» and

crank< and thfn undoing six screw~ .

Fig. 3. SchliisselgHat 41. Rear view .

~ -, ;c

~·

;c

-·~ .'..:

~

.(.'.

~ .. ;c

0 0 (} H 0 ..

f\) ..J CJr ..J 0 0 f\)

.... 'X

Schliisse lkasten (fi~'· .t and 5). T hese models , made by Fritz \1"nzer, 1n·rc devised to illustratr ce rtain asp~cls of the .,. 01kin2 of the Schhissclka sten. ,'\ o actual " orking models of this dc•·ice are H ailablt .

Fil(. ~ . Wooden model , presumably the sa rne size as the actual de vice, demonstrating the moverntnt of 1he ''> lide rule ."

r; ;i::; --'. ..,,, --; 0 r 0 C': r,

0

> ;;<;

er ;;<J r -<

0 0 (} H 0

I\) -J U1 -J 0 0 I\)

·-------------------------·----.. ···- - - · .. ·--·---····· ·-· ·- ·- · ..

,_, ·.D

Fig. 4. Wooden model, prrsumahl~· the ~ame ~iic as the ac tual derice. demonsttating the monment or thr "slide ruir .· ·

~ ... ' :·· .. t ' ~ ~

..... ·~ .... ";':::

fig . S. Wooden model powered with elastic bands demonstrating the rules or motion in the dHice. The disks . Tl - T4. represent 'lip wheels wh ich affect the relati>e posi tionini: of the fo ur pin wheels, G l-G4 . The hlack and white squares represent ac1ire and inactive pins . Dowels are insert ed in !he holes correspondin~ to positions where all holes arc acti>e or all inac ti>e. and ll and Z2 are pulled to the right and released . ~.ach time one of the four mttal

slips on Z2 encounters a dowel . the mechanism will qop and a cipher •·alue ma)' be read off uf SK I or SK:l.

-;z:

'

...,..,

"' N

~ er z " ,.,.,

"'

0 0 () 1-1 0

I\.) -J l11 -J 0 0 l'V

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took place. If the step came from A2 alone or A1 and A2 together, the slide took an additional step. When the slide stopped, either the top or the bottom alphabet would be in phase and the cipher value could be read off. Pressing the button again would allow the strip to slide left co its next stop. As mentioned at the beginning of this article, the Germans intended to replace many Enigmas with the Schliisselkasten. The device had a fairly high degree of security, as might be expected from a sliding strip system with irregular movement. Given the alphabets on the slide rule, it was possible to recover the pin patterns with a crib of about 30 letters. Without the crib, however, computer assistance would have been necessary; and large quantities of cipher would have been required to recover the alphabets. A modification was considered in which two 26-character alphabets were slid against one another, rather than the 13-character segments. This would have increased the device's security, since more text would have been required to recover the alphabets. It would, however, have simplified recovery of the pin patlern after alphabet recovery. In any case, solution of a single message was most unlikely. 17

The Sehl usse/seheibe. The Schliisselscheibe was designed by Menzer for use by clandestine agents. The operating principle was similar to that of the Schli.isselkasten. In the case of the Schli.isselscheibe, three resettable but permanently notched wheels were used. For encipherment, the inner disk was rotated to wind the spring. Pressing the key would then release the inner disk and allow it to rotate until stopped by the notch rings. If the inner disk stopped in a position where its letters were in phase with those of the outer disk, the cipher value would be read directly. If the stop was in an intermediate position, the number of the line opposite the plain value would be read, and the cipher value taken from the cell with that number. 18

The Sehl usse/rad. The Schliisselrad was a hand-operated cipher device designed for agent use. It was made up of two disks. The lower disk had 52 notches or holes around its edge, into which a pencil or stylus could be inserted to turn the disk. On the face of the disk were 52 cells into which a keyword-mixed alphabet could be inscribed twice, clockwise. The upper disk had a direct standard alphabet inscribed clockwise on one-half of its periphery, next to a semicircular window that, when the two disks were assembled concentrically, revealed 26 characters of the mixed sequence on the lower disk. The upper disk also had a notch cut into its edge which exposed ten of the holes on the lower disk. This notch had the digits 0 to 9 inscribed next to it, in a counterclockwise direction so that when the exposed holes were lined up with the numbers, the letters on the lower disk were lined up with the letters on the upper disk.

Various methods of key generation were used. On Chilean links, an 11-Jetter key word

was numbered as for a transposition key, with the first digit of two-digit numbers dropped. This key was extended by appending a two-digit group count and a four-digit time group:

ANTOFOGASTA

16074852913121440

On other links, a Fibonacci sequence of 100-125 digits would be generated through various manipulations of the date, time, and a secret number. If a message were longer than the key, it would be reversed as many times as necessary. Key generation tables were also used.

In use, the key constituted the input to an autoclave. After aligning the alphabets according to a prearranged system or according to an indicator in the message, a stylus was inserted in the hole corresponding to the first key digit, and the lower disk was rotated clockwise until the stylus was stopped by the end of the notch. The plain text letter was then found on the upper disk and its cipher value read off of the lower disk. The stylus

tTt'Xf continued n11 pogf! 35;

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Schliisselscheibe (figs. 6, 7, 8, and 9). 1 captured by the Russians to illustrate t

Fig. 6. Bakelite and aluminum model I cipher disk when the control lever (ali1

an e m the the

DOCID· 2757002 rRll7 \1ENZER TOP OEC~~T UIV\BRA

td a Schliis,el>cheihe (fii:s. 6. ', ~. and 9) . The'c modt-ls wur also made hy Fritz J\1cnur. .~II working modf'ls wen' Nilh captured b) th~ Russians t•J illus1ratc· the opH•ti<Jn of the de•·ice to Allied authorities.

the

mce I to

be1s 1ave

1he

1be1

by Jn

,1ere key ' Jf Jl e r

on, ken

:ent lge,

lisk [he :ry, lly , d a iad the up

Hd ed . >:

Jgh ger ere

1ets

113S

led ¥as !us

Fig. 6. Bakelit e and aluminum model powered "ith a rubber band . Demonstrates th<' mo•·ement or the central cipher disk when the control lcwr (aligned "ith line 10 in the photograph) is press<' d.

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.· ,-......<"' ..• : . . .. . - . -· . . \

. ' i ' ' I

11 ~ i

~i i:. 7. lJa~d i ll' and •lu111inu111 modd ilf u, traline inl t· rnal nm ~ ud no1ch »ht•t l opu a 1iv11 .

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DOCID: 2757002 FRITZ \1ENZrn TOR aeCRET UMORil:

<-: o:.. .,:l_,.,.

~~-

Fig. R. Brass model shol'l'ing cam and le»er operation.

1ternal cam and notch wheel operation.

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-.

1 2

fig. 9. Revetse of Hgure 8, showing slip whee ls .

TOf!! ~EC~ET UMEIFIA 34

1 I .

was then placed in the ho le con procedure was repeated for the sec. cipher was equal to the sum of all

JF

lf Menzer's devices bad been in certa inly have complicated the A ww;,ird so lution of Enigma traffic f been able to read German traffic . higher echelon communica tions. a l'ound to so lve Menzer's devices. E

w the British in 1939 , when they 1

GC&CS Who knows'> If the introductio

unwieldy bureaucracy , maybe Fritz

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- ' -

- . J.:...

~wing slip wb~els.

FRITZ MENZER I OP SECFtE r UMeF\A

was then placed in the hole corresponding to the second digit of key, and the same procedure was repeated for the second letter of text. Thus, the true key at any point in the cipher was equal lo the sum of all the previous key inputs (mod 26). 19

IF

If Menzer's devices had been introduced in a timely manner from 1940 on, they would certainly have complicated the Allied cryptanalytic effort, which was scrongly oriented toward solution of Enigma traffic from I 939 on . This is not to say that we would not have been able to read German traffic. The Germans did not intend to replace the Enigma on higher echelon communications, and in the face of necessity, methods would have been found to solve Menzer's devices. But we would have lost the edge that the Poles presented to the British in 1939, when they turned over the results of their analysis of the Enigma to GC&CS.

Who knows? If the introduction of his inventions had not been slowed down by an unwieldy bureaucracy, maybe Fritz could have won the war! ~o 1 . 4 . (c)

(S-Ce6) Since September 1981, Mr. Ma.wry has served as a historiah:J researching and writing a history o . ecently pub-lished in the Cryptologic 1story Series. He began his Agency careet as a Turkish linguist iii 1957 and later (1964-69) held an I position as ._I _____________ _

From 1969 through 1981 he served in various technical and mana erial ositioos in the

-~--.,..-......,..

Division. Mr. Mowry holds a 6A with regional group major in Germany cand Central Europe from the University ofC:alifor­nia at Berkeley and is certified as a Cryptana-lyst, Linguist, and Cryptologist; .. .

; ,~: 1. 4. ( c)

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NOTES

1 WDGAS-14, European Axis Signal Intelligence in World War fl as Revealed by "TICOM" lnw!Sligations and by Orher Prisoner of War Interrogations and Captured Material, Principally German, Vol. 2, p. 30.

2 79/49ff0PSEC/AS-141 t'-D~s.cription of Conlacts of Fricz Menzer wicb American and Sovie! Authorities and Summary of Career," p . 16. · .. ....

'Ibid., pp. 16-17.

•Ibid., p. 17 .

'Ibid., pp. 17, 18, and 21; and WDGAS-14, op. cit., Vol. 3, pp. 18-20.

· 6 Ibid., p. 21, and The History of Coast Guard Unit 387, pp. 156-211 . 1 79/49ff0PSEC/AS-14, op. cit., pp. 21-22. 8 Ibid., pp. a, b, and 6-7. 9 Ibid. , p. 9. 10 Ibid. , p. 10 . 11 Ibid., pp. 2, 4-15, and 22-23.

EO 1 . 4. ( c)

12 Ibid., p . 18; WDGAS-14, op. cit., pp. 22-23; and DF-174C, 11150/TOPSEC/AFSA, 14, "Remarks by Menzer on Various German Cryptographic Devices." January 1950, pp. l-2

11 79/49/TOPSEC/AS-14, op. cit., p. 19; and 115/49/TOPSEC/AS-14 _ l · Four Papers by Fritz Menzer," December 1949.

14 WDGAS-14, Vol. 2, op. cit. , p. 29. 15 "Report on SG 41 by Wilhelm Buggisch," 30 Augusl 1945. 16 Memorandum from Frank W. Le,js WDGAS-71 rp Cg!onel So!gmga Ku!!hack WDGt.S-70, "Study of the

C-41 Cipher Device," 4 March 1947_;! Jnd DF- 19, "Cipher Device-41," 10 January 1944. .- '----------------------'

11 79149/TOPSEC/AS-14, op. ci.t.·, pp. 31-32; 32151(f0PSEC/AFSA-14, R-1,· "Sch!iisselkasten 50," May 1951; and an undated, unsigned papj!i'. "Study of 'Schliisselkastcn'," in Folder S-14, 340 of the NSA Cryptologic Collection.

11

'-79_/_4-9/T_O_PS_E_C_/_A..,S ... -1_4_<i_p_c_jt_p_3_3_· _a_n_d_J_3_/5_1_.'10PSEC/ AFSA- 14. R-2 , "Schliisselscheibe 50," May 19 5 I . t ~ J

EO 1 . 4. (b)

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